1. Field of the Invention
The present invention relates to a drive control device of a vibration type motor, a device having the vibration type motor, and an image forming apparatus such as an electrophotographic printer, copying machine, or facsimile apparatus.
2. Related Background Art
Conventionally, a vibration type motor uses a vibration member. This vibration member is formed by adhering, with an adhesive, piezoelectric elements serving as electromechanical energy conversion elements to one surface of, e.g., a metal ring-like elastic member. Two standing waves are excited on the elastic member by applying alternative voltages having different phases to a driving piezoelectric element group formed on the piezoelectric elements, and generate a travelling vibration wave as a bending vibration by synthesizing these standing waves.
A member in, e.g., a ring shape, is pressed against the other surface of the elastic member via a press means, such as a spring. This member and an elastic member relatively move by frictional driving by the travelling vibration wave generated on the elastic member.
A the driving control device for controlling drive of the vibration type motor comprises a driving pulse generator for generating a driving pulse, and an alternative voltage generator, including a transformer, for generating alternative voltages having different phases applied to the piezoelectric element group in accordance with the driving pulse.
Since the vibration type motor has a high rotational precision and high resistance to transient load variations, a device using this vibration type motor as a driving source is advantageous in terms of color misregistration, pitch irregularity, paper feed shock, and the like. Thus, this device is proposed to be used as a driving device for a photosensitive drum of each color in an electrophotography color image forming apparatus, and a driving device for a driving roller for driving an endless transfer member convey belt, which sequentially conveys a transfer member to the transfer position of the photosensitive drum of each color.